Two cases of the potentially deadly coronavirus have been confirmed in South Australia, taking the national total to 12.

A couple in their 60s from the Chinese city of Wuhan, the epicentre of the outbreak, were visiting family in South Australia.

SA Health chief public health officer Nicola Spurrier on Saturday confirmed that the two new cases, a man and a woman, have been admitted to hospital with coronavirus.

“These cases were people that have come from Wuhan, China. They are visiting relatives in South Australia,” she said.

“They have followed all of the procedures and information that they have been asked to through communicable disease control branch.”

They developed symptoms and were tested at a public hospital before going into self-isolation.

Their relative has been tested, with results pending.

“We do not think there have been any contacts with anybody else in the state and they have been in self-isolation for the required time,” she said.

The couple is understood to have left Wuhan on January 20.

Twenty-five people have been tested in South Australia with 15 of those tests coming back negative earlier on Saturday.

The new cases came as Prime Minister Scott Morrison announced a ban on all foreigners who have left or passed through mainland China entering Australia.

Under the measure, travellers won’t be allowed to enter Australia for 14 days from the time they depart or transit through China.

SA Premier Steven Marshall said the state government would work hand-in-glove with the federal government to prevent the spread of the virus.

“We will be doing everything we can to make sure that they (South Australians) remain safe and we take every precaution possible to prevent the spread of this virus,” Mr Marshall said.

It will have “serious economic impacts” for South Australians, especially on international students and tourism, he added.

SA Health Minister Stephen Wade said he was confident the state’s hospital system could support the couple and South Australians.

“Our South Australian public health officials are world-class,” he said.

Australians are also being advised not to travel to mainland China as the number of confirmed coronavirus cases grows.

-AAP